Nebulizers are well known for dispensing medicament to the lungs of a patient for treating asthma, for example. A typical prior art nebulizer assembly for such therapeutic purposes includes a nebulizer which contains an electrically driven ultrasonic energy source and a dose cup acoustically coupled to receive ultrasonic energy from the source. A domed element is removably disposed over the dose cup, establishing a substantially closed mist chamber-defining element therein. An inhalation port extends from the domed element, permitting a user to inhale the contents of the mist chamber-defining element. The conventional practice of nebulizing an aqueous solution in ultrasonic (or jet) nebulizers, involves a first step of removing the domed element (permitting user access to the dose cup), followed by breaking an ampoule or vial containing the medicament, and introducing the contents into a dose cup or chamber. The domed element is then replaced, and the ultrasonic energy source is activated, whereby the ultrasonic energy is transmitted to the dose cup, where it nebulizes the medicament. A user may then inhale via the inhalation port, as desired.
The method of introducing the medicament to the dose cup involves prolonged handling of the medicament by the patient and therefore may lead to hygiene issues and volume loss due to spillage or incomplete emptying of the ampoule. A further issue is the number of components which require cleaning following nebulization—dose cup, domed element, inhalation ports of the inhalation port, for example.
It is an object of this invention to provide an improved nebulizer apparatus and method which minimizes spillage of drug and the number of components to be cleaned.
Another object is to provide an improved nebulizer. Most conventional nebulizers allow free flow of air through a dose chamber during nebulization, which results in the exhalation of the patient forcing nebulized mist back into the dose chamber and device during exhalation. As a consequence, a large proportion of the dose condenses on the inside of the device and is therefore not delivered to the lung. It is another object of this invention to provide more efficient air control during inhalation and particularly exhalation, to significantly improve nebulizer performance.